How to find the reverse of each word in a given sentence ?

package pack1;

public interface ReversingEachWordIntf {

	/* Define the functional interface with SAM 'ParseEachWord' */
	StringBuffer ParseEachWord(String str1);

	/* Define the static method 'displayMsg' */
	static void displayMsg(String inpSen, StringBuffer pniSen) {

		System.out.println("This sentence '" + inpSen + "' after reversing '" + pniSen + "'");
		System.out.println("\n");
	}
}

package pack1;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import java.util.Optional;
import java.util.StringTokenizer;
import java.util.logging.Logger;
import java.util.stream.Collectors;

class InputSequenceOfStrings {

	private String strParam;

	/* Declare the logger object for the class to display the log messages */
	static Logger logger = Logger.getLogger(InputSequenceOfStrings .class.getName());

	public boolean validateInputs(String inpSentence) {

		/* Fetch the class object's name from which this method is called */
		String cName = Thread.currentThread().getStackTrace()[2].getClassName();
		String mName = "validateInputs()";
		logger.info("This method '" + mName + "' called from the Class '" + cName + "'");

		/* Validating the function parameters using Optional String data type methods */
		Optional<String> strInput = Optional.ofNullable(inpSentence);

		/*
		 * Fetch the value of the Optional String parameters using 'isPresent' condition
		 * check. If the value is available use 'get' method otherwise simply return
		 * 'false' to stop the program execution without proceeding further.
		 */
		if (strInput.isPresent()) {
			setStrParam(strInput.get());
		} else {
			return false;
		}

		logger.info("The provided Input validated Successfully");
		return true;
	}

	/* Define getter and setters for strParam variables */
	public String getStrParam() {
		return strParam;
	}

	public void setStrParam(String strings) {
		this.strParam = strings;
	}
}

class ReversingEachWord_Using_StringBuffer extends InputSequenceOfStrings implements ReversingEachWordIntf {

	public StringBuffer ParseEachWord(String inpSentence) {

		/* Fetch the class object's name from which this method is called */
		String cName = Thread.currentThread().getStackTrace()[2].getClassName();
		String mName = "ParseEachWord";
		logger.info("This method '" + mName + "' called from the Class '" + cName + "'");

		StringBuffer resultStr = new StringBuffer();

		if (validateInputs(inpSentence)) {

			System.out.println("The given input sentence is = '" + inpSentence + "'");
			/* Traversing through each word of the sentence, and then reverse each token */
			StringTokenizer words = new StringTokenizer(inpSentence);
			while (words.hasMoreTokens()) {
				StringBuffer nextWord = new StringBuffer(words.nextToken());
				nextWord.reverse();
				resultStr.append(nextWord + " ");
			}

		} else
			logger.info("The given Input sentence is null");

		ReversingEachWordIntf.displayMsg(inpSentence, resultStr);
		return resultStr;
	}
}

class ReversingEachWord_Using_String extends InputSequenceOfStrings implements ReversingEachWordIntf {

	public StringBuffer ParseEachWord(String inpSentence) {

		/* Fetch the class object's name from which this method is called */
		String cName = Thread.currentThread().getStackTrace()[2].getClassName();
		String mName = "ParseEachWord";
		logger.info("This method '" + mName + "' called from the Class '" + cName + "'");

		String resultStr = new String("");
		if (validateInputs(inpSentence)) {

			System.out.println("The given input sentence is = '" + inpSentence + "'");
			/* Split the input sentence into list of words with space as delimiter */
			List<String> words = Arrays.asList(inpSentence.split("\\s"));

			/*
			 * Pass each word to the reverse function which returns the reversed string
			 * value
			 */
			for (int i = 0; i < words.size(); i++) {
				resultStr = resultStr + ReversingEachWord(words.get(i)) + " ";
			}

		} else
			logger.info("The given Input sentence is null");

		ReversingEachWordIntf.displayMsg(inpSentence, new StringBuffer(resultStr));
		return new StringBuffer(resultStr);
	}

	private String ReversingEachWord(String strVar) {
		/* Using basic logic of storing characters in the reverse order */
		String strRev = "";
		for (int i = strVar.length() - 1; i >= 0; i--)
			strRev = strRev + strVar.charAt(i);
		return strRev;
	}
}

class ReversingEachWord_Using_LambdaExp extends InputSequenceOfStrings implements ReversingEachWordIntf {

	public StringBuffer ParseEachWord(String inpSentence) {

		/* Fetch the class object's name from which this method is called */
		String cName = Thread.currentThread().getStackTrace()[2].getClassName();
		String mName = "ParseEachWord";
		logger.info("This method '" + mName + "' called from the Class '" + cName + "'");

		/* Define the Lambda expression for the functional interface 'ParseEachWord' */
		ReversingEachWordIntf Rew = ((Sentence) -> {
			/*
			 * Process each word in a Sentence, and store in 'resStr' StringBuffer variable
			 */
			StringTokenizer allWords = new StringTokenizer(Sentence);
			StringBuffer resStr = new StringBuffer();
			while (allWords.hasMoreTokens()) {
				StringBuffer nextWord = new StringBuffer(allWords.nextToken());
				resStr.append(nextWord.reverse() + " ");
			}
			return resStr;
		});

		StringBuffer resultStr = new StringBuffer();
		if (validateInputs(inpSentence)) {
			System.out.println("The given input sentence is = '" + inpSentence + "'");
			/* call the lambda expression */
			resultStr = Rew.ParseEachWord(inpSentence);
		} else
			logger.info("The given Input sentence is null");

		ReversingEachWordIntf.displayMsg(inpSentence, resultStr);
		return resultStr;
	}
}

class ReversingEachWord_Using_Stream extends InputSequenceOfStrings implements ReversingEachWordIntf {

	public StringBuffer ParseEachWord(String inpSentence) {

		/* Fetch the class object's name from which this method is called */
		String cName = Thread.currentThread().getStackTrace()[2].getClassName();
		String mName = "ParseEachWord";
		logger.info("This method '" + mName + "' called from the Class '" + cName + "'");

		ArrayList<StringBuffer> arrListStrs = new ArrayList<StringBuffer>();
		if (validateInputs(inpSentence)) {

			System.out.println("The given input sentence is = '" + inpSentence + "'");
			/* Split the input sentence into list of words with space as delimiter */
			String[] arrStrs = inpSentence.split("\\s+");
			for (String str : arrStrs)
				arrListStrs.add(new StringBuffer(str));

			/* Applying map() of stream, and reverse () of string buffer */
			arrListStrs.stream().map(s -> s.reverse()).collect(Collectors.toList());

		} else
			logger.info("The given Input sentence is null");

		ReversingEachWordIntf.displayMsg(inpSentence, new StringBuffer(Arrays.toString(arrListStrs.toArray())));
		return new StringBuffer(Arrays.toString(arrListStrs.toArray()));
	}
}

public class ReversingEachWordJ8 {

	public static void main(String[] args) {

		/*
		 * create the class object ReversingEachWord_Using_StringBuffer, and call the
		 * method ParseAlphanumeric
		 */
		ReversingEachWord_Using_StringBuffer REWUStrB = new ReversingEachWord_Using_StringBuffer();
		REWUStrB.ParseEachWord("Java developers are in demand");
		REWUStrB.ParseEachWord(null);

		/*
		 * create the class object ReversingEachWord_Using_String, and call the method
		 * ParseAlphanumeric
		 */
		ReversingEachWord_Using_String REWUStr = new ReversingEachWord_Using_String();
		REWUStr.ParseEachWord("Python Scripting is good learning");
		REWUStr.ParseEachWord(null);
		REWUStr.ParseEachWord("");
		/*
		 * create the class object ReversingEachWord_Using_LambdaExp, and call the
		 * method ParseAlphanumeric
		 */
		ReversingEachWord_Using_LambdaExp REWULamda = new ReversingEachWord_Using_LambdaExp();
		REWULamda.ParseEachWord("Javascript is double ended sword");
		REWULamda.ParseEachWord(null);
		REWULamda.ParseEachWord("");
		/*
		 * create the class object ReversingEachWord_Using_Stream, and call the method
		 * ParseAlphanumeric
		 */
		ReversingEachWord_Using_Stream REWUStream = new ReversingEachWord_Using_Stream();
		REWUStream.ParseEachWord("NodeJs is powerful");
		REWUStream.ParseEachWord(null);
		REWUStream.ParseEachWord("");
	}
}